1. Field of the Invention
The present invention relates to a system and method for inspecting a semiconductor device, and more particularly, to a system and method suitable for inspecting a semiconductor device whose terminals are formed from solder balls and protrude from a package.
2. Description of the Background Art
FIGS. 9 and 10 show inspection sockets which have conventionally been used for inspecting a semiconductor device of ball grid array (BGA) type or a semiconductor device of chip-size package (CSP) type. In FIGS. 9 and 10, reference numeral 10 designates the bottom of a package of a semiconductor device which is an object of inspection. Further, reference numeral 12 designates a solder ball provided as a terminal on the bottom 10 of the package.
An inspection socket 14 shown in FIG. 9 is of leaf spring type. A leaf spring 16 is provided on an interface substrate (simply called IF substrate) 15. Further, the inspection socket 14 is provided with a slide guide for adjusting the position of the leaf spring 16. The leaf spring 16 clamps the solder ball 12 from both sides thereof by means of elastic force of the leaf spring 16, thus achieving desired contact.
An inspection socket 17 shown in FIG. 10 is of POGO type, and has an extendable POGO pin 18 provided on the IF substrate 15. A semiconductor device is set on the IF substrate 15 such that each of the POGO pins 18 comes into contact with the corresponding solder ball 12, whereby the inspection socket 17 of this type can achieve desired contact.
In the case of the inspection socket 14 of leaf spring type shown in FIG. 9, the leaf spring 14 must provide sufficient elastic force. Therefore, a comparatively long distance; particularly, a distance of about 10 mm, must be ensured between the IF substrate 15 and the solder ball 12. Inductance arising between the IF substrate 15 and the solder ball 12 increases with the distance therebetween. A signal exchanged between the IF substrate 15 and the solder ball 12 is degraded in, particularly, a high-frequency range, as inductance existing between the IF substrate 15 and the solder ball 12 becomes greater. For this reason, the inspection socket 14 of leaf spring type is not suitable for high-speed testing of a semiconductor device.
The inspection socket 17 of POGO pin type shown in FIG. 10 achieves desired contact by means of applying contact pressure to the solder ball 12 from below. The contact pressure acts as a load on a package of the semiconductor device. The load imposed on the package increases with the number of pins of the semiconductor device. If excessive load is exerted on the package, the semiconductor element provided within the package will be damaged. For this reason, the inspection socket 17 of POGO pin type has a problem of being likely to inflict damage on a semiconductor device having a plurality of pins.
The present invention has been conceived to solve such a drawback of the background art and is aimed at providing an inspection system for inspecting at high speed a semiconductor device having a plurality of pins.
The present invention is also aimed at providing an inspection method of inspecting at high speed a semiconductor device having a plurality of pins.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.